Temporary change IP on Microsoft servers and wait for resolution from SpamCop.
Just for a record - 184.108.40.206/71 has no any reverse DNS records. Something that is a must for legitive servers.
this and find that there is even more funny results. 220.127.116.11 reversed to tide137.microsoft.com thich give only one incorrect IP 18.104.22.168 in return.
Or 22.214.171.124 -> tide143.microsoft.com -> No record.
This is plain wrong and a subject to fix.
I understand that there can some misterious reasons inside Microsoft to create following configuration - but they are unknown to me.
IT inside Microsoft are paid well to be able correct this in 1 hour ;o))